This invention relates to the use of certain phosphorus-containing compounds that can act at low concentrations as stabilizers for polyolefins against degradation caused by heat, mechanical stress or light. They are especially suitable for polyolefins which have been made with a 11 and higher generation catalyst (e.g. II to V generation catalysts).
According to the invention, there is provided a polyolefinic composition comprising:
a) a compound of formula I to III 
xe2x80x83in which
each R1 independently is selected from linear or branched C1-30alkyl, C5-12cycloalkyl, C2-24alkenyl, C2-18alkoxyalkyl, C2-19alkanoylmethylene, C7-30alkaryl, C7-30aralkyl, C4-24heteroaryl where any one of the above substituents of R1 are unsubstituted or are substituted by 1 to 3 groups selected from C1-12alkyl, xe2x80x94OR4, xe2x80x94NR4R5, xe2x80x94COR4 and xe2x80x94COOR4); and C6-30aryl, unsubstituted or substituted by 1 to 5 groups R3 selected from C1-12alkyl, C18alkoxy, C5-6cycloalkyl, phenyl or phenoxy, xe2x80x94OR4, xe2x80x94NR4R5, xe2x80x94COR4 and xe2x80x94COOR4,
R4 and R5 independently are selected from hydrogen, C1-30alkyl (linear or branched), C5-12cycloalkyl, C6-24aryl, C7-30alkaryl or C7-30aralkyl;
A is a direct bond, a group xe2x80x94(Pxe2x80x94R1)pxe2x80x94 or an n-valent aliphatic or aromatic residue, preferably C1-30alkylene (linear or branched), C5-12cycloalkylene, C7-30alkarylene, C7-30aralkylene, C6-24arylene, a Nxe2x80x94, Oxe2x80x94, Sxe2x80x94, or Pxe2x80x94 containing C6-24heteroarylene, C2-30alkylidene or C2-30alkylene interrupted by N, O or S;
m is 3 to 12 preferably 4-6;
n is 2 to 5; and
p is 1 to 12; preferably 1-5;
(the compounds of formulae I to III hereinafter being called xe2x80x9ccomponent axe2x80x9d); and
b) a polyolefin which has been produced in the presence of a Ziegler or metallocene type catalyst which has not been removed (hereinafter called xe2x80x9ccomponent bxe2x80x9d).
For the avoidance of doubt, compounds of formula III are cyclic compounds.
In the compounds of Formula I, when n is 2 and A is C1-3alkylene, A in such a case is preferably xe2x80x94CH2xe2x80x94 or C5-30alkylene.
Preferred compounds of formula I are of formula Ia
(R1xe2x80x2)3Pxe2x80x83xe2x80x83(Ia)
in which
each R1xe2x80x2 independently is selected from C8-18alkyl, C6-18aryl, C4-12heteroaryl, C2-18alkoxyalkyl, C7-30alkaryl, C7-30aralkyl, C2-19alkanoylmethylene, or a group of formula xcex3
in which
each R3 is independently selected from C1-8alkyl, C1-8alkoxy, C5-6cycloalkyl, phenyl or phenoxy; and
q is 1 to 5; preferably from 1 to 3.
Preferred compounds of formula II are of formula IIa
Axe2x80x2xe2x80x94(P(R1xe2x80x2)2)nxe2x80x2xe2x80x83xe2x80x83(IIa)
in which
each R1xe2x80x2 independently is selected from C8-18alkyl, C6-18aryl, C4-12heteroaryl, C2-18alkoxyalkyl, C7-30alkaryl, C7-30aralkyl, C2-19alkanoylmethylene or a group of formula xcex3
in which
each R3 is independently selected from C1-8alkyl, C1-8alkoxy, C5-6cycloalkyl, phenyl or phenoxy; and
q is 1 to 5; preferably from 1 to 3; and
Axe2x80x2 is selected from C1-12alkylene, C1-12alkylidene, C6-18arylene, C4-12heteroarylene, C5-12alkylene, C12-18cycloalkylene, phenoxyphenylene, C3-18alkylaminoC1-12alkylene; and
nxe2x80x2 is 2 to 4.
Preferred compounds of formula III are of formula IIIa
 greater than (Pxe2x80x94R2xe2x80x2)mxe2x80x2xe2x80x83xe2x80x83(IIIa)
in which
each R2xe2x80x2 independently is C1-12alkyl, cyclohexyl, methyl or C6-12aryl; and mxe2x80x2 is 4 or 5.
More preferred compounds of formula I are of formula Ib
(R1xe2x80x3)3Pxe2x80x83xe2x80x83(Ib)
in which
each R1xe2x80x3 independently is selected from C10-18alkyl, C6-12aryl, C4-10heteroaryl, C3-18alkoxyalkyl, C2-19alkanoylmethylene, C7-24alkaryl, C7-24aralkyl, or a group of formula xcex3
in which
each R3 is independently selected from C1-8alkyl, C1-8alkoxy, C5-6cycloalkyl, phenyl or phenoxy; and
q is 1 to 5; preferably from 1 to 3.
More preferred compounds of formula II are of formula IIb
Axe2x80x3xe2x80x94(Pxe2x80x94(R1xe2x80x2xe2x80x3)2)nxe2x80x3xe2x80x83xe2x80x83IIb
in which
each R1xe2x80x2xe2x80x3 independently is selected from C10-18alkyl, C4-9heteroaryl, C7-24alkaryl, C4-18alkoxyalkyl or of formula xcex3
in which
each R3 is independently selected from C1-8alkyl, C1-8alkoxy, C5-6cycloalkyl, phenyl or phenoxy; and
q is 1 to 5; preferably from 1 to 3;
Axe2x80x2 is selected from C2-12alkylene, C2-12alkylidene, C6-12arylene, C2-12alkoxyalkyle phenoxyphenylene, C4-10heteroarylene, C6-8cycloalkylene, C3-12alkylaminoalkylene; and
nxe2x80x3 is 2 to 4.
Most preferred are of formula I are of formula Ic
(R1xe2x80x2xe2x80x3)3Pxe2x80x83xe2x80x83(Ic)
in which
each R1xe2x80x2xe2x80x3 independently is selected from C10-18alkyl, C4-9heteroaryl, C7-24alkaryl, C4-18alkoxyalkyl or of formula xcex3
in which
each R3 is independently selected from C1-8alkyl, C1-8alkoxy, C5-6cycloalkyl, phenyl or phenoxy; and
q is 1 to 5; preferably from 1 to 3.
Most preferred compounds of formula II are of formula IIc
Axe2x80x2xe2x80x3xe2x80x94(Pxe2x80x94(R1xe2x80x2xe2x80x3)2)nxe2x80x2xe2x80x3xe2x80x83xe2x80x83(IIc)
in which R1xe2x80x2xe2x80x3 is as defined above;
Axe2x80x2xe2x80x3 is selected from C5-12alkylene, C6-12arylene, C4-12alkoxyalkylene, phenoxyphenylene, C4-9heteroarylene, cyclohexylene, cyclooctylene, C3-8alkyl-aminoalkylene; and
nxe2x80x2xe2x80x3 is 2 or 3.
The compounds of formulae I to III may be made from known compounds by known methods. Reviews of such reaction procedures are given in e.g. G. M. Kosolapoff, Organic Phosphorus Compounds, Vol. 1-7, Wiley, New York, 1972 or Houben/Weyl, Methoden der Organischen Chemie, Vol. 12, 4. Auflage, Georg Thieme Verlag, Stuttgart 1963 and corresponding supplementary volumes. The contents of which are incorporated herein by reference.
Compounds of Formula II wherein A is a direct bond and compounds of Formula III are also prepared by a process which comprises reacting either a secondary phosphine of the formula R1R1PH or a primary phosphine of the formula R1PH2 with a halogen, preferably chlorine or bromine, in the presence of an acid acceptor, for example, an oxide, hydroxide, or carbonate of an alkali or alkaline earth metal or an amine, preferably a tertiary amine, optionally in the presence of an inert solvent. Secondary phosphines result in compounds of Formula II wherein A is a direct bond. Primary phosphines result in compounds of Formula III. Advantageously, this process uses as starting materials alkyl phosphines which are more readily available than the halophosphines that are used in the art.
Typically those compounds are prepared from organohalides such as alkyl- or aryl chlorides or alkyl or arylbromides and PCl3 via a Grignard or modified Wurtz reaction; via Friedel-Crafts reaction; by addition of Pxe2x80x94H containing compound to multiple bonds; by Arbuzov reaction of diorganophosphinites with organohalides and subsequent reductions; or by derivation from already formed phosphines.
Compounds of formula I to III of special interest are selected from:
Tris-octyl-phosphine
Tris-decyl-phosphine
Tris-dodecyl-phosphine
Tris-tetradecyl-phosphine
Tris-hexadecyl-phosphine
Tris-octadecyl-phosphine
Tris-benzyl-phosphine
Phenyl-dibenzyl-phosphine
Diphenyl-benzyl-phosphine
Tris(1-phenylethyl)phosphine
Phenyl-di(1-phenylethyl)phosphine
Diphenyl-(1-phenylethyl)phosphine
Tris(2-phenylethyl)phosphine
Phenyl-di(2-phenylethyl)phosphine
Diphenyl(2-phenylethyl)phosphine
Tris(2-phenyl-2-methylethyl)phosphine
Phenyl-di(2-phenyl-2-methylethyl)phosphine
Diphenyl(2-phenyl-2-methylethyl)phosphine
Tris(2-methyl-phenyl)phosphine
Tris(4-methyl-phenyl)phosphine
Tris(2-ethyl-phenyl)phosphine
Tris(4-methyl-phenyl)phosphine
Tris(2-tert-butyl-phenyl)phosphine
Tris(4-tert-butyl-phenyl)phosphine
Tris(2-butyl-phenyl)phosphine
Tris(4-butyl-phenyl)phosphine
Tris(2-octyl-phenyl)phosphine
Tris(4-octyl-phenyl)phosphine
Tris(2,4-dimethyl-phenyl)phosphine
Tris(2,6-dimethyl-phenyl)phosphine
Tris(2,4-diethyl-phenyl)phosphine
Tris(2,6-diethyl-phenyl)phosphine
Tris(2,4,6-trimethyl-phenyl)phosphine
Tris(2,4,6-triethyl-phenyl)phosphine
Tris(2,4-di-tert-butyl-phenyl)phosphine
Tris(2,6-di-tert-butyl-phenyl)phosphine
Tris(2,4-dibutyl-phenyl)phosphine
Tris(2,6-dibutyl-phenyl)phosphine
Tris(2,4,6-tri-tert-butyl-phenyl)phosphine
Tris(2,4,6-tributyl-phenyl)phosphine
Tris(2,4-dioctyl-phenyl)phosphine
Tris(2,6-dioctyl-phenyl)phosphine
Tris(2,4,6-trioctyl-phenyl)phosphine
Diphenyl-octyl-phosphine
Diphenyl-decyl-phosphine
Diphenyl-dodecyl-phosphine
Diphenyl-tetradecyl-phosphine
Diphenyl-hexadecyl-phosphine
Diphenyl-octadecyl-phosphine
Phenyl-di-octyl-phosphine
Phenyl-di-decyl-phosphine
Phenyl-di-dodecyl-phosphine
Phenyl-di-tetradecyl-phosphine
Phenyl-di-hexadecyl-phosphine
Phenyl-di-octadecyl-phosphine
Tris(2-methoxy-phenyl)phosphine
Tris(4-methoxy-phenyl)phosphine
Tris(2-butoxy-phenyl)phosphine
Tris(4-butoxy-phenyl)phosphine
Tris(2-octoxy-phenyl)phosphine
Tris(4-octoxy-phenyl)phosphine
Tris(2-phenoxy-phenyl)phosphine
Tris(4-phenoxy-phenyl)phosphine
Tris(2,4-dimethoxy-phenyl)phosphine
Tris(2,6-dimethoxy-phenyl)phosphine
Tris(2,4,6-trimethoxy-phenyl)phosphine
Tris(2,4-dibutoxy-phenyl)phosphine
Tris(2,6-dibutoxy-phenyl)phosphine
Tris(2,4,6-tributoxy-phenyl)phosphine
Tris(2,4-dioctoxy-phenyl)phosphine
Tris(2,6-dioctoxy-phenyl)phosphine
Tris(2,4,6-trioctoxy-phenyl)phosphine
Tris(2,4-diphenoxy-phenyl)phosphine
Tris(2,6-diphenoxy-phenyl)phosphine
Tris(2,4,6-triphenoxy-phenyl)phosphine
Tris-1-naphthylphosphine
Tris-2-naphthylphosphine
Tris-2-biphenylylphosphine
Tris-3-biphenylylphosphine
Tris-4-biphenylylphosphine
Tetraphenyl-ethylene-diphosphine
Tetraphenyl-propylene-diphosphine
Tetraphenyl-butylene-diphosphine
Tetraphenyl-hexylene-diphosphine
Tetraphenyl-octylene-diphosphine
Tetraphenyl-c-hexylene-diphosphine
Tetraphenyl-c-octylene-diphosphine
Tetraphenyl-phenylene-diphosphine
Tetraphenyl-biphenylene-diphosphine
Tetraphenyl-phenoxyphenylene-diphosphine
Hexaphenyl-triphenyleneamino-triphosphine
2,4,6-tris-diphenylphosphino-s-triazine
Tris-2-pyridinylphosphine
Tris-2-quinolinylphosphine
Hexaphenyl-3-tripropyleneamino-trisphosphine
Hexaphenyl-2-tripropyleneamino-triphosphine and
Tris(octadecenoyl-methylene)phosphine
The compounds of formula III are cyclic, compounds in which the P atoms form the ring with a pendant R1 group.
Preferably component a) is present in an amount of 0.005-5%, more preferably 0.02-1% based on the weight of the polymer present in the composition.
The term metallocene is used to describe new catalysts of generation V and higher which are used to produce polyolefins (especially polyethylenes and polypropylenes) as described for example in xe2x80x9cModern Plasticsxe2x80x9d 10/91 p. 46-49 and in xe2x80x9cMakromolekulare Chemiexe2x80x9d, 192, 1059 (1991). The supported Ziegler catalysts (such as those supported on a halogen containing magnesium compound) are well known and are described in Table 1 below.
Further additives which may be added to a polymeric composition according to the invention include antioxidants, such as sterically hindered phenols, secondary aromatic amines or thioethers, (as described in xe2x80x9cKunststoff-Additivexe2x80x9d -Gxc3xa4chter/Mxc3xcller, Ed. 3, 1990 p.42-50, the contents of which are incorporated herein by reference); acid scavengers such as sodium, magnesium and calcium stearates and lactates, zinc oxide hydrotalcite or alkoxylated amines; U.V. stabilizers such as other sterically hindered amines (for example N-unsubstituted, N-alkyl or N-acyl substituted 2,2,6,6-tetra-methylpiperidine compounds) [also known as hindered amine light stabilizers-HALS] and U.V. absorbers (e.g. 2-(2xe2x80x2-hydroxyphenyl)-benztriazoles, 2-hydroxybenzophenones, 1,3-bis-(2xe2x80x2-hydroxy-benzoyl) benzene salicylates, cinnamates and oxalic acid diamides), U.V. quenchers such as benzoates and substituted benzoates, antistatic agents, flameproofing agents, lubricants, plasticisers, nucleating agents, metal deactivators, biocides, impact modifiers, fillers, pigments and fungicides.
Component a) may be added to the polymeric material before, during or after the polymerization step and may be added in solid or molten form, in solution preferably as a liquid concentrate containing from 10 to 80% by weight of the composition and 90 to 20% by weight of solvent or as a solid masterbatch composition containing 10 to 80% (more preferably 40 to 70%) by weight of the composition and 90 to 20% (more preferably 60 to 30%) by weight of a solid polymeric material which is identical with or compatible with the material to be stabilized.
Component a) may be incorporated by known methods into the polymeric material to be stabilized. Of particular importance is dry-blending of component a) with the polymer or coating shaped polymer particles, e.g. polymer spheres, or in the form of a liquid, a solution or a suspension/dispersion. Of particular importance is blending of the compounds with thermoplastic polymers in the melt, for example in a melt blender or during the formation of shaped articles, including films, tubes, fibres and foams by extrusion, injection moulding, blow moulding, spinning or wire coating. Component a) is particularly useful for stabilizing polypropylene and polyethylene articles of every type as well as polycarbonate, polystyrene and polyurethane.
Component a) is especially suitable for use in polyolefins and especially xcex1-polyolefins prepared using processing catalysts known as Generation II to Generation V catalysts and which have not been subjected to a catalyst removal step. By the term xe2x80x9ccatalyst removal stepxe2x80x9d used herein is meant a step for the purpose of positively removing the catalyst residues contained in the polymerized polyolefins or treating the polyolefins with the compound which can react with the catalyst residue and inactivate or solubilize the residue, such as alcohols or water, and then removing the inactivated or solubilized catalyst residue by physical means such as filtration, washing and centrifuging. Thus, in the case of suspension polymerization, the step of separating the resulting polymer from a dispersion medium, such as a solvent or a liquefied monomer, does not fall under the above-mentioned definition of the catalyst residue removal step, although the catalyst dissolved in the dispersion medium may be removed by a separation step. The step of adding a small amount of catalyst poisons such as ethers, alcohols, ketones, esters and water to the resulting polymer, to inactivate the catalyst remaining after the completion of polymerization, or the step of treating the resulting polymer suspension with gas such as steam or nitrogen to remove the dispersion medium also does not fall under the above-mentioned definition of the xe2x80x9ccatalyst residue-removalxe2x80x9d step.
What is meant by Generation I catalysts is titanium halide catalysts and an organo aluminium compound or an organo aluminium halide.
What is meant by Generation II catalysts is Generation I catalysts supported on an organo magnesium compound or based on an organo chromium compound supported on SiO2.
What is meant by a Generation III catalyst is a Ziegler type complex catalyst supported on a halogen containing magnesium compound.
What is meant by a Generation IV catalyst is a Generation III catalyst with a silane donor.
What is meant by Generation V catalysts is a bis-indenyl organo titanium compound supported on alumoxane or bis cyclopentadienyl titanium halides activated by aluminium alkyl compound.
Further generations of highly specific catalysts, especially useful for manufacturing highly stereoregular poly-xcex1-olefins, which are presently under development, are included in the concept of II and higher Generation catalysts, as well as the abovementioned generations of supported catalyst systems.
Examples for the microstructure of such highly stereoregular polyolefins are given by syndiotactic polypropylene, isotactic stereoblock polymers, isotactic polypropylene containing stearic defects randomLy distributed along the polymer chain (so called anisotactic polypropylene) or stereoirregular stereoblock polymers. Due to the rapid progress in the development of newer generation catalyst systems, the commercial significance of these polymers with novel, highly interesting properties is increasing. However, residues of such further catalyst generations, as long as they contain metals of the 3d, 4d and 5d series of the periodic system supported analogously to the earlier catalyst generations, can also cause disadvantageous properties in the polymer, as long as such residues are still present in the polymer even if in a deactivated form. In view to this, it can therefore be expected that component a) according to the invention is also suitable for overcoming such disadvantageous properties of the polymer. This means that any disadvantageous interaction between processing stabilizers and the aforementioned residues of catalysts of further generations, particularly the hydrolysis of phosphites and phosphonites, is most effectively inhibited.
These generations of catalysts are described in the publication of the Twelfth Annual International Conference on Advances in the stabilization and Controlled Degradation of Polymers held in Luzern, Switzerland, 21-23 May 1990 in an article on pages 181 to 196 inclusive by Rolf Mxc3xclhaupt entitled xe2x80x9cNew Trends in Polyolefin Catalysts and Influence on Polymer Stabilityxe2x80x9d. The contents of this article is incorporated herein by reference and especially Table I on page 184 describing the Generation of Catalysts:
in which R, in Table 1, is an organo group; HDPE is high density polyethylene, LLDPE is linear low density polyethyene, Cp is cyclopentadienyl, Et is ethyl, PP is polypropylene and MWD is molecular weight distribution.
Further, in this specification, where a range is given, the figures defining the range are included therein. Any group capable of being linear or branched is linear or branched unless indicated to the contrary.
For the avoidance of doubt, in this specification t-butyl means tertiary butyl, (xe2x80x94C(CH3)3).